Vane structure for rotary pumps



1942. w. H. CURTIS 2,282,642

VANESTRUCTURE FOR ROTARY PUMPS Filed May 17, 1940 2 Sheets-Sheet 2' g 54 5:1? \\\\\\\\\I y A, 5

ATTORNEY.

Patented May 12, I942 VANE srnoc'rnm: non no'rAaY PUMPS William H. cur-us, Dayton, ohm,

minor to Curtis Pump Company, Dayton, Ohio, a corporation of 01110 Application May 17, 1M0, Serial N0. 335,703 I 2 maims. (61. 1433-137) This invention relates to rotary pumps of the sliding vane type and more particularly to the vane structure of pumps of this character.

In one form of pump 'of this class it is the general practice to so slot the rotor that the vanes may extend diametrically through and beyond the rotor, opposite ends of each vane being at all times in contact with the cylinder bore.

' Vanes of this construction are usually called through vanes, since a vane extends from the inner wall of the cylinder bore through a rotor slot and to the opposite wall of the cylinder bore, the width of the vane corresponding to the axial length of the insideof the cylinder.

If one only of this kind of vane were used in a rotor, the width of the vane could be uniform from end to end, but since it is the general practice to employ two or more such vanes in angularly spaced rotor slots, the vanes must cross each other within the rotor, and part of each vane must therefore be cut away at its middle portion where it interferes with the other or others.

Where two through vanes are employed, the most common practice, in vane construction, is to out half of the width of each vane away midway of its length, the out being preferably slightly longer than the stroke of the blade plus its thickness, whereby one vane will always clear the other where they cross within the rotor. This conventional vane structure, however, gives satisfactory service only at moderate rotative speeds for the following reasons:

At each revolution of the rotor, a vane necessarily moves transversely in the rotor slot to one extremity of its travel, pauses, then moves transversely in the slot back to the beginning, the cylinder bore being appropriately shaped to cause such movement of a vane by bearing in all rota-tive positions against the ends thereof.

It follows that when the rotative speed is as great as several thousand R. P. M., inertia forces of considerable moment must be overcome by the cylinder wall in starting the vane in its transverse movementf'and in stopping it after it has moved the required distance.

Where, therefore, each vane has its clearance cut extending in at one edge through half its width, the uncut half of the vane has much greater weight than the notched half, whereby the inertia forces of any vane are greater in one half than in the other, resulting in an uneven wear in the cylinder bore.

It is therefore an object of this invention to providea vane structure wherein each vane is perfectly symmetrical, to the end that the inertia forces of a vane on be the same throughout the cylinder wall will the cylinder length.

Another object is to so construct and arrange to the rotor and its slots,

the vanes with respect that the vanes may be quickly and easily assembled in the rotor.

That these and other objects and advantages are had in the illustrative embodiment disclosedwill become more apparent as the invention is further described with reference to the drawings,

wherein,

Fig. l is a longitudinal axial section, taken at 5-! of Fig. 2, through a pump embodying the principles of my invention;

Fig. 2 is an axially transverse section through the pump taken at 2-2 of Fig. 1;

3 is a plan view of one of the vanes;

Fig. 4 is a plan view of a half vane, two of these parts being used in the assembly to constitute one vane;

Fig. 5 is a longitudinal axial section through the rotor;

Fig. 6 shows the rotor of Fig. 5 after one of the half vanes has been assembled therein;

, Fig. '7 shows the assembly Fig. 6 comprising the rotor with the half vane inserted and the whole vane in the process of being inserted;

other half vane in the Fig. 8 shows the assembly Fig. 7, but after the whole vane has been fully inserted;

Fig. 9 shows the assembly Fig. 8, with the process of insertion; and Fig. 10 shows the complete rotor and vanes assembled. Like numerals refer to like parts throughout the drawings.

Construction The rotor 26 shown in detail in Fig. 5 is ro-- tatabLv supported at the rear end in the cover 22 by the small ball bearing 28, and at the front or drive end in the body It by a larger ball bearing 80, A slotted driving lug 32 is tightly se-' cured in the driving end of the rotor for connectlon to a flexible drive mean (not shown).

At its rear end the rotor 26 has a smallhub 34 extending into the ball bearing 28, and a. shorter but larger hub 36 fitting freely into the' as illustrative of them-1 l2 with interchangesame here which contains the bearing 28. At its front or drive end, the rotor has a small hub 38 extending into the ball bearing 80, and a shorter but larger hub 40 fitting freely into the same bore which contains the bearing 80.

Four circumferentially equally spaced slots 42 I extend longitudinally through the rotor, the

depth of the slots being such that they extend radially inward through the outside of the larger -hubs 36 and 40 but not to the smaller hubs 34 and 38. I

In order that the slots at the outside of the rotor may provide ample bearing for the vanes, and a more effective seal between the rotor and the vanes, the ribs 44 are formed on the inside of the rotor at as many points as there are slots to be cut in the rotor. Care mustof course be exercised that, when the slots are cut, they are located centrally of the ribs.

Fig. 3 shows a vane 46, the shorter edges 48 of which preferably corresponds exactly to the axial length of the rotor between the hubs 86 and 40, which isalso the axial length of the cylinder IS. The longer edges are provided with equal notches 58 the notches being of such depth as to leave a bridge 52 connecting the wider parts, this bridge, in the instant case being approximately one third the whole width of the vane.

Fig. 4 shows a half vane 54, the shorter edges 55 of which are exactly half the dimension of the edge-. 48 of the whole vane. Equal notches 58 in the sides leave a bridge 68 approximately one third the width of the half vane. It'wili be noticed that both the whole and the half vanes are perfectly symmetrical. The reason for this symmetry, as before mentioned, is to maintain equal inertia forces of the vanes against the cylinder throughout its axial length. The reason for the particular shape and proportions of the vanes is to facilitate assembly of the varies with the rotor, as will appear from Figs. 6 to 10.

The procedure in assembling the vanes in the rotor comprises placing a half vane 54 in a slot and moving it to the extreme left as in Fig. 6, with the edges 62 extending beyond their ultimate position in the assembly Fig. 1. The whole vane 46 is now inserted in a slot ninety degrees rotation from the first used slot, the edge 84 being hooked over and under the bridge 68 of the inserted half vane as in Fig. '7, then swung around until straight, then moved to the left as far as it will go as in Fig. 8, the bridge 52 being new against the bridge 60.

With a half vane 54 and a whole vane 48 in-' serted as in Fig. 8, and displaced to the extreme left as shown, there is new space available in the slot 42 to insert the wide part of the other half vane 54 as in Fig. 9. When this second half vane is inserted as far as the first, the vanes rotor made in halves with screws extending axially therethrough to hold the two halves together, merely in order that. a symmetrical vane structure might be employed and assembled therein, the advantages of the vane structure herein disclosed will be obvious, for, in the complete assembly, the vanes are symmetrical and yet the rotor is of integral construction.

I claim:

1. A rotor and vane assembly for pumps comprising a rotor provided with intersecting slots therethrough, a symmetrical I-shaped vane with wide heads seated in one slot to provide balanced blades on opposite. sides of the rotor connected by a single web, a pair of smaller symmetrical I-shaped vanes in the other slot with aligned heads providing balanced blade portions on opposite sides of the rotor between the firstmentioned blades, and each opposite blade portion being connected by a single web whereby one small vane can have the web thereof initially seated at an end of its slot, the wide-headed vane can be cooked into its slot around the web of the inserted vane to bring its web into abutment with fining a pump chamber. a rotor mounted in said casing andvanes slidabl carried by said rotor,

the improvements which comprise said rotor provided with intersecting slots therethrough, said slots having open-ended outer portions and closed-ended intermediate portions, a symmetrical I-shaped vane having the web thereof slidably disposed in the intermediate portion of a slot and having wide heads slidably seated in the open-ended outer portions of the same slot to provide a pair of balanced blades on opposite sides of the rotor engaged along their lengths by the slot, a pair of smaller symmetrical I- shaped vanes having the webs thereof slidably disposed in the intermediate portion of the other slot on opposite sides of the web of the wideheaded vane, said pair of vanes having the heads thereof in aligned relation to define a second pair of balanced blades on opposite sides of the rotor and between the first-mentioned blades, and said second pair of blades also being engaged along their lengths by the other slot. whereby one of web of the wide vane.

WILLIAM H. CURTIS. 

